Investigation And Evaluation Of Precious Native Broad-leaved Timber Species In Guiyan

To accelerate the cultivation of precious native broad-leaved timber species in China has become the most important work in forestry development Guizhou province is one of the most typical karst landforms in southwest China,and it is also one of the key forest areas in south China.Guiyang is located in the hinterland of central Guizhou,and its unique natural ecological environment provides a favorable natural foundation for the cultivation of precious native broad-leaved timber trees in Guiyang city is rich in precious wood plant resources,but not many species have been developed and utilized,especially the cultivation of precious local broadleaf tree species is less.This paper carries out field investigation on the precious local broadleaf tree species and plant resources of Guiyang city,market research,literature research and expert consultation by data collection and analysis,this paper discusses the selection index of precious local broadleaf tree species in Guiyang,selects and evaluates precious local broadleaf tree species in Guiyang,and carries on afforestation division of precious broadleaf tree species in Guiyang.The main research results are as follows:（1）There were 26 species of precious native broad-leaved timber trees in Guiyang,belonging to 15 families and 20 genera,and 5 species of plants with higher resource level（plant number:N>1 000）.There were 2 species with medium resource grade（500<N<1 000）.17 species were rare（N≤200）,and 16 species were sporadic.3 species were distributed in sheets;Scattered distribution of the three species;2 species were scattered.（2）Among the 26 precious local broadleaf tree species,zelkova and Sorbus were distributed in all county units of Guiyang city.There were 2 species with more than 5units in distributed counties.There were 7 species with only 1 unit in the distribution county.The most species were found in the range of 300～2200 m and 700～1500 m.（3）Among the county units in the study area,Xifeng County had the most precious native broad-leaved timber species.The second is Kaiyang County and Huaxi District;The number of tree species distributed in Guanshan Lake district was the least,and the similarity coefficient between the two counties ranged from 0.166 to0.998.The lowest similarity was found in Yunyan District and Kaiyang County,and the highest similarity was found in 5 pairs of counties that showed significant correlation between Yunyan District and Baiyun District.There were 2 pairs of counties that showed extremely significant correlation.（4）In the constraint layer of the timber value evaluation model for timber species,the comprehensive weight value of timber property（B₁）（0.4073）was the largest,followed by the suitability（B₃）（0.3608）,and the value（B₂）（0.2319）.The total weight order of each index relative to standard layer is:durability>rapidity>economic value>use value>widespread>resistance>strength>density>high yield>color>structure>texture>cultural value>dimensional stability.（5）The coefficient of variation was as follows:cultivability（19.2503）>value（18.0545）>material property（15.8642）>comprehensive score（10.7196）.The range of fertility score was the largest（1.9415）,and the dispersion degree was large.（6）The grade I（>7.5）and grade II（6.5～7.5）were good wood species.There were 9 species in both grades,accounting for 34.62%of the total.8 species,accounting for 30.77%,were classified as gradeⅲ（<6.5）.